In a method of depositing a silicon oxide film using bis(diethylamino)silane (BDEAS) on a substrate in a reaction space by plasma-enhanced atomic layer deposition (PEALD), each repeating deposition cycle of PEALD includes steps of: (i) adsorbing BDEAS on the substrate placed on a susceptor having a temperature of higher than 400° C. in an atmosphere substantially suppressing thermal decomposition of BDEAS in the reaction space; and (ii) exposing the substrate on which BDEAS is adsorbed to an oxygen plasma in the atmosphere in the reaction space, thereby depositing a monolayer or sublayer of silicon oxide.